The present invention relates to a component recognition apparatus installed in industrial automated facilities, and more particularly to an image acquiring device of the component recognition apparatus.
The prior art will be discussed below with reference to FIG. 7. FIG. 7 is a block diagram showing the constitution of a conventional component recognition apparatus, in which reference numerals 11, 12 and 31-33 are a component holding nozzle, an electronic component to be recognized, a CCD camera, an illumination device and a lens barrel respectively. The operation of a conventional image acquiring device in the thus-constituted recognition apparatus will now be depicted. Referring to FIG. 7, the component 12 held by the component holding nozzle 11 is temporarily stopped on a vertical line of the CCD camera 31, where the component is recognized. At this time, the electronic component 12 is illuminated by the illumination device 32 with a sufficient amount of light for exposure. After an advancing direction of light is changed by the lens barrel 33, the light is taken into the CCD camera 31 and then, the component is moved to a next stage. The illumination device 32 used here is constituted of, e.g., a plurality of LEDs arranged on a board to uniformly illuminate the whole view field for the electronic component. For example, when the electronic component is 60 mm.times.60 mm, the illumination device 32 is so designed as to uniformly illuminate the 60 mm.times.60 mm view field. For this purpose, in the prior art a diffusing plate or a like arrangement is inserted to prevent an illumination irregularity.
In acquiring an image of the electronic component with the use of a line sensor as the camera, an acquiring line of the line sensor is overlapped with the electronic is component thereby to set a size of the view field. Therefore, if the electronic component is scanned at high speed, the resulting scarcity of illuminance may lead to a shortage of electric charges of photodetecting elements. If a light source is lowered in height to increase the illuminance of the acquiring line in the event that the light source shows a high directivity, the illuminance of the acquiring line is apt to be irregular.